In the treatment of various diseases, percutaneous access to the peritoneal cavity is necessary. An example is peritoneal dialysis which is often indicated for acute or chronic renal failure. To effect dialysis through the peritoneal cavity, a percutaneous passage is surgically formed through the cutaneous and subcutaneous tissues, rectus muscle and through the peritoneum itself. This passage permits insertion and implantation of a distal portion of the catheter within the peritoneal cavity. A separate caudally directed tunnel is then formed through the subcutaneous and cutaneous tissues with a tunnel exit site in the supra pubic region of the external abdominal wall. A proximal portion of the catheter is inserted into the tunnel thereby maintaining an end of the proximal portion in a downward direction along the abdominal wall. Examples of catheters used in peritoneal dialysis include those disclosed in U.S. Pat. Nos. 3,633,585; 4,184,497; 4,278,092; 4,279,252; 4,368,737; 4,392,855; 4,681,570; 4,687,471; 4,772,269; and 4,935,004.
One example of peritoneal dialysis catheters, the Tenckhoff catheter is commercially available and widely used with patients who must undergo chronic peritoneal dialysis for maintenance in the absence of normal kidney function. The catheter is made of silicone rubber, and has a pair of porous tissue attachment cuffs in spaced relation to each other, so that after implantation of the catheter into the abdominal wall, tissue grows into pores of the cuffs, for secure and permanent anchoring of the catheter in place. Tenckhoff et al., "A Bacteriologically Safe Peritoneal Access Device", Trans. Am. Soc. Artif. Intern. Organs 14:181-187 (1968).
A significant problem with peritoneal dialysis catheters is the risk of post-operative infection, typically infection of the tunnel exit site. The prior art has attempted to address the problem of infection by the use of "swan neck" catheters which are disclosed in U.S. Pat. No. 4,687,471 and 4,772,269 ('471 and '269).
Not withstanding the suggestions of '471 and '269, there remains a need for peritoneal dialysis catheters which reduce the risk of tunnel exit site infection.